The US Food and Drug Administration (FDA) has approved a New Drug Application (NDA) for Somaxon Pharmaceuticals’ Silenor (doxepin) to treat insomnia characterised by difficulty with sleep maintenance.

The drug is recommended for patients with the most commonly reported symptoms of insomnia who wake frequently during the night and are unable to return to sleep.

Silenor has now been approved for the treatment of transient (short term) and chronic (long term) insomnia, characterised by difficulty with sleep maintenance in adults and elderly patients.

Approval was based on clinical trials, which demonstrated maintenance of sleep into the seventh and eighth hours of the night, with no meaningful evidence of next-day residual effects.

Silenor has not been designated as a controlled substance by the US Drug Enforcement Administration because of its demonstrated lack of abuse potential.

Somaxon president and chief executive officer Richard W Pascoe said that Silenor’s ability to treat sleep maintenance insomnia without meaningful next-day residual effects and without abuse potential uniquely positions the drug for commercial success.

“We will prepare to launch Silenor in the second half of 2010,” Pascoe said.